1. Field of the Invention
The present invention relates to an incubator which continuously heats a test strip to a predetermined temperature and maintains it at that temperature and which an analyzer incorporates therein for performing quantative analysis of a sample of a person's blood, serum or plasma and more particularly to a thick-film incubator which is compact and has very fast response time.
2. Description of the Prior Art
U. S. Pat. No. 4,584,275, entitled Incubator, issued to Shinichi Okano, Takashi Koizumi and Tasashi Uekusa on Apr. 22, 1986, teaches an analyzing system which includes an incubator, a light source and a photodetector. The incubator includes a heating plate, a heating element, a temperature detector and a temperature control circuit. The heating plate is made of aluminum and is maintained at a predetermined temperature according to reaction conditions. The incubator uniformly heats analysis slides to a predetermined temperature. The standard temperature for blood samples is 37.degree. C. The heating plate has a hole adjacent to the analysis slide. A dark box is disposed below the hole and encloses the light source, a lens, a color filter and the photodetector. The light source applies light through the hole in the heating plate. In an analyzer a microprocessor may be electrically coupled to the temperature control circuit, the light source, the photodetector and a display. The microprocessor analyzes the output of the photodetector and transmits the analyzed output to the display.
U.S. Pat. No. 4,620,437, entitled Gas Sensor, issued to Yoshiaki Kuroki, Toshitaka Matsuura, Toshofumi Sekiya and Akio Takami on Nov. 4, 1986, teaches a gas sensor which includes a ceramic substrate and a heater circuit. The heater circuit has a first terminal and a second terminal at opposite ends thereof. The heater circuit is mounted on the substrate. The heater circuit has a heat-generating portion and a voltage-dividing portion connected to the second terminal. A voltage source applies a voltage through a resistive lead wire element to energize the heater circuit.
U.S. Pat. No. 4,613,455, entitled Ceramic Heater and a Method for its Production, issued to Hirofumi Suzuki, Shunzo Yamaguchi and Hitoshi Yoshida on Sept. 23, 1986, teaches a ceramic heater which includes a sintered heating element bonded to a supporting substrate.
U.S. Pat. No. 4,469,936, entitled Heating Element Suitable for Electric Space Heaters, issued to James B. Hunter on Sept. 4, 1984, teaches a heat generating element which is for use in an electrical space heater and which include an electrically nonconductive substrate on which is coated a layer of an electrically nonconductive ceramic material having finely divided, micron size metallic particles dispersed therein. Burnishing the surface of the ceramic material between two separated points establishes a conductive path in the otherwise nonconductive ceramic material. As electrical current flows along the burnished surface, the electrical resistance of the conductive path generates heat.
U.S. Pat. No. 4,464,244, entitled Oxygen Sensing Device Having Solid Electrolyte Cell and Means for Supplying Controlled Current Thereto, issued to Shigeo Isitani and Uchida Masaaki on Aug. 7, 1984, teaches a heater which includes a ceramic substrate and a heating element in operative combination therewith. A power supply applies a variable voltage to the heating element in the ceramic substrate in order to maintain the heater at a predetermined temperature by controlling the resistance of the heating element at a constant value.
U.S. Pat. No. 4,523,853, entitled Medical Test Reaction Area Reflected Light Photometric Device, issued to Klaus Nenninger and Rudolf V. Rosenbladt on June 18, 1985, teaches a reflected-light photometer which includes a light source, an integrating sphere and a photodetector. The light source diffusely illuminates the reaction area of a test strip through the integrating sphere. The photodetector directly picks up reflected light which the top chemical layer of the test strip at the reaction area diffusely reflects therefrom. Reflectance is the measure of light which the chemical layer of the test strip at the reaction area diffusely reflects therefrom. The reflected-light photometer determines reflectance of the top chemical layer of the test strip at the reaction area.
U.S. Pat. No. 4,587,099, entitled Test Strips for the Detection of a Liquid Sample Component, issued to Anselm Rothe and Bernward Sojka on May 6, 1986, teaches a test strip for analyzing a liquid sample. The test strip has a carrier, a slow-absorbent layer, a liquid impermeable layer, a reagent-absorbent layer, and a thin mesh. The slow-absorbent layer is fixed upon the carrier and slowly absorbs a sample of a person's blood, serum or plasma. The liquid impermeable layer is fixed over the slow-absorbent layer. The reagent-absorbent layer is fixed over the liquid impermeable layer and forms the top chemical layer. The thin mesh covers the carrier, the slow-absorbent layer, the liquid impermeable layer and the absorbent reagent layer. The thin mesh is fixed next to the slowly-absorbent layer onto the carrier.